Molding process and molded article



Jan. 7, 1936. w. H. WOODFORD 2,026,765

MOLDING PROCESS AND MOLDED ARTICLE Filed July 25, 1932 FIG. I

Fig. 5

INVENTOR.

' WATSON H.WoouFoRu ATTORNEY Patented Jan. 7, 1936 I UNITED STATESMOLDING PROCESS AND MOLDED ARTICLE Watson H. Woodford, Bridgeport,Conn., assignor to Remington Arms Company, Inc., a corporation ofDelaware Application July 23, 1932, Serial No. 624,325

20 Claims.

This invention relates to the molding of articles from fibrous pulp, andwill be described with particular reference to wads for shot shells,although its novelty and utility are not limited to these particulararticles.

Shot shell wads are of at least three distinct types, each type servinga particular purpose in the shot shell. The bas'e" wad, which is a wadof very substantial thickness in comparison with its diameter, isprovided with a central aperture and pressed into the base of, the shellopposite the metallic head thereof and between such head and the batterycup. Its primary function is to effect a seal between the interior ofthe shell and the joint between shell body and head, thereby preventingthe escape of powder gases. A suitable charge of powder is placed uponthe base wad, and upon the powder is located an overpowder wad usuallyof a type of paper of a thickness of the order of 6" to A". Theover-powder wad is comparatively dense and non-resilient. Upon theover-powder wad are placed one or more filler wads usually of some typeof hair felt. These wads are much more resilient than the over-powderwad and are designed to be pressed into close engagement with the boreof the shot gun, thereby effectually preventing the escape of powdergases around their peripheries into the shot charge. The edges of thefiller wads are lubricated with such a substance as stearine, chieflyfor the purpose of providing a lubricated surface on the gun bore andpreventing abrasion of the shot and consequent leading of the bore. Thelubricant must substantially penetrate the periphery of the wad, inorder to prevent its complete removal in the cone of choke boredbarrels, and consequent leading beyond this point.

The present invention is directed primarily to filler wads, although itlikewise contemplates over-powder wads and base wads of essentially thesame construction and made by processes substantially similar to thosepracticed in the pro duction of filler wads.

One object of the present invention is to provide a process for theindividual molding of shot shell wads from asuspension of the wadforming materials in a fluid medium.

A further object of the invention is to control the characteristics andquality of the wads by suitable regulation of the concentration of thewad forming materials in. the fluid medium.

A further object contemplates the development of, a process of wadforming which includes the utilization of large quantities of scrapmaterial resulting from the manufacture of filler wads as hithertopracticed.

The invention further contemplates the accurate control of the densityand other physical characteristics of wads by the accurate regulation ofthe quantity of material entering into each wad.

The invention further contemplates wads and other articles molded frommaterials of a fibrous character in such a manner as to prevent the lay-1 ing of, the fibres in plane substantially parallel to the wad surfacesand the consequent tendency of the wads to split into thin sheets.

The invention further contemplates wads having an improved capacity forabsorbing a lubricant-and retaining such lubricant under temperaturesabove its melting point.

With these and other objects in view the invention consists in the novelarticles and methods of their production to be hereinafter more fullydescribed.

In the drawing:

Fig. 1 is a fragmentary sectional elevation of one form of apparatusused in the practice of the novel processes of the present invention.This showing of the apparatus is somewhat diagrammatic.

Fig. 2 is a fragmentary sectional elevation, partly in section, of apart of the apparatus shown in Fig. 1, positioned beneath the wadforming compression plungers.

Fig. 3 is a view similar to Fig. 2, showing the wad in the mold aftercompression by the plunger.

Fig. 4 is a fragmentary sectional'elevation of a mold and plungeradapted to produce an aper- 5 tured wad.

Fig. 5 is a perspective of a filler wad.

Fig. 6 is a perspective of an apertured wad as formed in the mold shownin Fig. 4.

Fig. 7 is a fragmentary side elevation of a 40 slightly modified form ofmold charging tube and adjacent part of the mold.

Fig. 8 is a sectional elevation of a wad produced by the apparatus ofFig. 'l.

The wad forming materials utilized in the present invention may be anysuitable granular or fibrous materials capable of suspension in water orother suitable fiuid medium. Preferably, the wad forming composition isa mixture of a relatively coarse fibrous material, such as hair, with arelatively fine and partially hydrated material, preferably wood pulp;and a somewhat granular filler material, such as sawdust. Any of thesematerials, or mixtures of any two or all three of them, in varyingpercentages produce wads of excellent properties for one or more of thethree purposes hereinbefore mentioned. A suitable composition for fillerwads comprises hair in proportions varying between 40% and 90%, sawdustin an amount of 10% to 25%, and wood pulp in an mount of to 100%. Thehair may be derived from scrap felt, a large amount of such scrapresulting from the cutting of hair felt wads from large sheets.Approximately 35% of such sheets is scrap, and it'has been foundimpracticable to rework this scrap into other sheets. The wood pulp maybe either sulphite pulp stock or scrap news print paper.

A typical composition for filler wads comprises 20% sawdust, 60% scrapfelt, and 20% newspaper or sulphite pulp.

A typical composition for over-powder wads comprises 20% scrap felt orother fibre, such as jute fibre, 40% sawdust, and 40% newspaper.

A typical base wad comprises about 40% sawdust and 60% newspaper orsulphite pulp.

The process for forming wads from such materials as follows:

The scrap felt and news print paper or sulphite pulp, being properlydisintegrated, are introduced with the desired amount of sawdust into asuitable tank or container a part of which is identified by the numeralin Fig. 1. The sulphite pulp or newspaper is disintegrated by mechanicalworking to a suflicient extent, but not to a point where it loses itsfibrous character or the individual fibres become highly hydrated orgelatinous. It is essential that the fibrous character of the pulp bemaintained in order to avoid such a cohesion between the fibres as wouldresult in a rigid, non-resilient article. The suspension of the wadmaterials in the tank is maintained at a fairly low concentration, andis agitated by suitable means to maintain all portions thereof at thedesired concentration. Concentrations up to 10% are permissible, but aconcentration of the order of 1% is preferable.

Suitable means are provided for withdrawing measured portions of thesuspension of wad forming materials from the tank and introducing theminto a wad forming mold. For this purpose, the tank may be provided withany desired number of tubes H extending through the bottom of the tankand upward to a, point well above the top of the pulp suspension,indicated by dotted line l2. Surrounding each tube II is a measuring cupl3 of suitable construction and connected with suitable devices for itselevation from the position within the pulp suspension, shown in fulllines in Fig. 1, to a position adjacent ,the top of the tube II, asshown in-dotted lines in Fig. 1. As each cup 13 is elevated to thedotted line position its contents are discharged into the tube I I andfall through said tube and a suitable connecting tube or sleeve l4 intoa mold l5. Each mold I5 is fixed in a dial plate It supported above andclosely adjacent to a fixed bed plate H.

For the production of wads of the order of A" to 'in thickness, mold l5preferably has a height of about 3". Both ends of the mold wall aresolid, while its intermediate portion is provided with suitablyproportioned drainage perforations or slots 20. Each connecting sleevei4 is arranged to fit inside of its associated mold l5 and to be drawnslowly upwardly as the pulp suspension settles in the mold. The timeoccupied in withdrawing the sleeves l4 varies from 2 to 5 seconds,depending on the particular composition used.

Each mold l5 when in position to receive :1.

charge of wad forming materials through the tube II is aligned with aperforated bushing l8 in the bed plate H. The perforations l9 of saidbushing provide a vertical drainage for the pulp suspension fluid, whilethe slots 20 of the mold l5'providealateral drainage. i

The sleeve I4 is provided primarily for the purpose of preventing theescape of too large a quantity of the pulp forming material through theslots 20 before it has had an opportunity to settle, and said sleeve l4iswithdrawn at such a rate that only a very small quantity of the pulpescapes through or enters the slots 20. i

The charge for a typical wad comprises 80 c. c. of the pulp suspension,which consists of substantially '79 c. c. of water and 1 c. c. of pulp.Before and during the withdrawal of the sleeve I4 about 10 c. c. of thefluid escapes through the bottom drainage perforations I9 and about 59c. c. escapes through the lateral drainage perforations or slots 20. Ofthe remaining 10 c. c. of fluid, 9 c. c. is expelled in the pressingoperation which will now be described.

The molds I5 being thus charged with accurately measured quantities ofwad forming pulp, the dial plate 16 is indexed to a position in whichthe molds l5 are positioned beneath a set of wad forming plungers 2|(Fig. 2). again, aligned with perforated bushings in the .bed plate, l1,which bushings are substantially similar to the bushings I8 alreadymentioned. The plungers 2| are now lowered, compressing the pulp andexpelling about 90% of the remaining fluid through both the drainageslots 20 and the apertures IS, the downward movement of c the plungersbeing stopped at a distance from the bottom of the molds correspondingto the desired thickness of the wad. If desired, an upward verticaldrainage, as'well as a downward vertical drainage, may be provided bythe use of perforations 22 in the heads of plungers 2|, as clearly shownin Fig. 3.

It has been found that the combination of lateral drainage through theslots 20 with downward vertical drainage through the bottom apertures l9and, if desired, an upward vertical drainage through the apertures 22,is effective to prevent the laying of the fibres in planes parallel tothe wad surfaces, and the resultant lamination or cleavage along suchplanes which characterizes practically all products hitherto made frommolded fibrous pulp. The paper wads hitherto used, particularly asover-powder wads, are very highly laminated and upon firing of the shellthey split into thin sheets which scatter about, obscuring-the shooter'sview of the results of the shot. A similar characteristic is possessedby all prior articles of molded fibrous pulp. While solid articles havebeen molded from pulp which has been beaten and hydrated to such anextent that thefibres are disintegrated or gelatinized until theirfibrous character is lost and under compression they adhere and form' asubstantially rigid, non-resilient and non-fibrous article, the

present invention is believed to constitute the first process of moldingfibrous articles of substantial thickness showing no cleavage. Thisresult moreover is secured without the use of any binder whatever.Ordinary hair felt wads contain a very substantial percentage of abinder, yet the wads of this invention, with no binder at all, show afar greater resistance to tearing parallel to their faces than hair feltwads containing large quantities of binder.

Apparently three factors are involved in the The molds l5 are securingof wads of substantial thickness which are resilient, porous enough totake a lubricant,

and show no cleavage or lamination parallel to,

their faces. The first factor is the presence of a substantial amount ofgranular, material,- of which sawdust has been given as an example. Itis a familiar fact in the manufacture of paper and pulp articlesgenerally that in the formation of laying of the fibres which results intransverse cleavage is the large and controlled lateral drainage. Onlyabout 25% of the fluid escapes through the face of the wad, and of thisabout half is pressed out after the wad material has become soconcentrated as to prevent free movement of the fibres. The remaining75% or more of the fluid escapes through the lateral drainage apertures;thus, the fibres tend strongly to be aligned in a directionperpendicular to the wad faces and directly across the usual planes ofcleavage.

The third factor is the application of pressure to the wad faces. Alarge portion of the fibres being arranged substantially perpendicularto the wad faces, this pressure is applied to'them endwise, and resultsin diagonal displacement, curling and crinkling, which completes theirfelting into such a tangled mass as to prevent any tendency to cleavage.

A wad having concaved faces, as illustrated in Fig. 8, may be formed byintroducing the charge of pulp suspension into the mold 15 in such a waythat it acquires a whirling motion, and removing the sleeve while thesuspension is still in motion. One means of accomplishing this result isillustrated in Fig. 7 in which the opening from the tube ll into sleeveI4 is adjacent one wall of said sleeve. The pulp of the suspensionsettles while it is being urged outwardly by the centrifugal action ofthe whirling suspension, and a wad with concaved faces results eventhough a fiat faced punch 2| and a fiat drainage bushing I8 of the typeshown in Figs. 2 and 3 are used. Other desired shapes of wads may besecured by suitably forming the pulp engaging face of the plunger and/orthe face of the drainage bushings l8.

An apertured wad (Fig. 6) suitable for or to be subsequently shaped intoa base wad, may be made by the use, in the mold l5, of a suitable core24, shown in Fig. 4 as supported in the sleeve It by a spider 23. Saidcore, however, may be supported in any other convenient manner, and ifdesired a corresponding projection may be formed on the wad compressingplunger 2| to better preserve the aperture formed by the core.

The wads having been compressed to the desired thickness, as heretoforedescribed, the plungers 2| are withdrawn and the dial plate 16 is againindexed to bring the molds I5 over apertures in the bed plate. llthrough which the wads are removed from the molds by suitable knock-outpunches. The wads are subsequently dried under normal atmosphericconditions to remove the remaining moisture, and their edges aresubsequently lubricated with a suitable lubricant such as stearine orpetrolatum. It has been found that such pulp wads have the capacity forretaining the necessary amount of such lubricant at temperaturesat whichthe lubricant becomes quite fluid, whereas ordinary hair felt wads donot under these conditions retain the lubricant. Such a loss oflubricant from the edges of felt wads has in the past been the cause ofmany complaints of poor combustion of powder. Under summer storageconditions the wad lubricant becomes quite fluid and may work past theover-powder wad and into the powder charge with a resulting injurythereto. The wads of this invention will retain indefinitely a muchgreater quantity of lubricant than is necessary for the purposeshereinbefore explained, at temperatures substantially above the highesttemperatures of storage conditions. Moreover, the invention offers forthe first time a practicable means of accurately controlling thethickness, density and rigidity of wads. It is quite impracticable tomanufacture sheets of felt or other material which are of uniformthickness, different parts of the sheets substantially vary inthickness, and the wads cut therefrom varyaccordingly. invention anaccurately measured quantity of material enters into each wad and thisquantity of material is pressed to a predetermined thickness. Greateruniformity in ballistics of shells, as well as superior lubrication andthe absence of deterioration due to the escape of lubricant, are thussecured.

The embodiments of the invention and the processes herein are typicaland illustrative only, the invention being susceptible to practice inother ways and by means of other apparatus,

all falling within the scope of the appended claims. Y

What is claimed is: I

l. The method of making a shot shell wad which comprises the placing ofa measured by an imperforate sleeve during charging, the

withdrawal of said sleeve as the wad forming material settles in saidmold, and the subsequent compression of said materials to form a wad.

3. The method of making a wad having a thick peripheral flange and .athin center which comprises charging a measured quantity of a suspensionof wad forming materials into a mold in such a manner as to cause'thesuspension to revolve in said mold.

4. The method of making a wad having a thick peripheral flange and athin center which comprises charging" a measured quantity of asuspension of iorming materials into a mold in such a manner as to causethe suspension to revolve insaid mold, and subsequently compressing saidmaterial under a die.

5. The methodof making shot shell wads which comprises the charging of ameasured quantity of a suspension of the wad forming materials into amold arranged for lateral drainage and containing an imperforate shield,and the withdraw- Under the practice of the present form a non-laminatedarticle of subst'antial thickmass which comprises the charging of ameasured quantity of a pulp'sus'pension' into a mold p'r o vided withlater'al and vertical drainage apertures, and the shielding of thevertic'al drainag'e apertures during the charging operation A l 7. Inthejmanufacture of shot shell wads, the method which comprises moldingfrom a fluid suspension of a mixture of fibrous and granular materials,and varying the amount oflateral drainage during the molding operation,8. In the manufacture of shot shell wads, the

method which comprises molding from a fluid suspension of fibrecontaining material under fixed axial drainage andvariable lateraldrainage. 9. In the manufacture of shot shell wads, the method whichcomprises molding from a fluid suspension of a mixture of long fibres,short fibres. and a granular material, under fixed drainage in onedirection and variable drainage in another direction. I

10.'In.the manufacture of shot shell wads, the method which comprisesmolding from a'fiuid suspension of a mixture of fibrous materials and agranular filler material under conditions or fixed axial drainage and alateral drainage controlled to enable partial settling of the suspendedmaterials prior to exposure to lateral drainage.

11. In the manufacture of shot shell wads fconn prising fibrousmaterials, the method of felting the fibres into a resilient,coherent,'unlaminated structure which comprises molding a fluidsuspension of said fibrous materials and a granular material whileproviding a fixed drainage in one direction and controlling drainage inanother direction so as to permit partial settling of the suspendedmaterials before draining in said seconddirection.

12. In the manufacture of shot shell wads com prising fibrous materials,the method of felting the fibres into a resilient, coherent, unlaminatedstructure which comprises molding a fluid suspension of said fibrousmaterials and a granular material while providing a fixed drainage inone direction and controlling drainage in another direction so as topermit partial settling of the suspended materials before draining insaid second direction, the amount of controlled drainage substantiallyexceeding the amount of fixed drainagd '13. In the manufacture ofshotshell wads comprising 'fibrousrnaterials, the ineth'odfof feltingthe fibres into a resilient, coherent; unlam'inated structure whichcomprises'molding a fluid susmold" during the settling" of the charge,releasing the supernatant liquid "laterally from saidrnold,-, 1 andcompressing the charge. v

v 15. In the manufacture of shot she'll wads ',"the method whichcomprises introducing into :a mold aicharge of a fluid suspension of amixture of fibrous and granularmaterials, allowing a settling of saidcharge in said mold,ireleasing' the supernatant liquid laterally fromsaidmold, and compressing the charge. i" v 16. In the individualmoldingof shot shell 'wads, the methodwhich comprises the addition to a,fluid suspension of fib're'sf of from 10% to 40% of sawdust, and themolding of the fib'er sawdust mixture into shot shell wads which arecoherent inuse.

17. A coherent gun wad molded from a waterlaid mass of .a fibrousmixture including hair, wood pulp and sawdust, theisawdust constituting10% to 40%. of the wad according to its intended use.

18. A coherent gun wad molded from a waterlaid massvof a fiber mixtureincluding hair, Wood pulp and, sawdust, wherein the fibrous contentvaries'from 45% upward and the sawdust content varies froin 10% to 40%according to the 40 intended use. of thewad. i I

' 19. A coherent gun wad molded from a waterlaid mass of a fiber mixtureincluding hair, wood pulp and sa'wdust, in the following proportions"?20. A coherent gun wad-molded from a waterlaid mass of a mixture of afibrous materialv and sawdust, the sawdust being present in an amountbetween 10% and depending upon themtended use of thewad.

hair, 20% to 90%; wood pulp, 10% to 60%; sawwA'rsoN H. WOODFORD.

